DESCRIPTION

mq_receive()
removes the oldest message with the highest priority from
the message queue referred to by the message queue descriptor
mqdes,
and places it in the buffer pointed to by
msg_ptr.
The
msg_len
argument specifies the size of the buffer pointed to by
msg_ptr;
this must be greater than or equal to the
mq_msgsize
attribute of the queue (see
mq_getattr(3)).
If
msg_prio
is not NULL, then the buffer to which it points is used
to return the priority associated with the received message.

If the queue is empty, then, by default,
mq_receive()
blocks until a message becomes available,
or the call is interrupted by a signal handler.
If the
O_NONBLOCK
flag is enabled for the message queue description,
then the call instead fails immediately with the error
EAGAIN.

mq_timedreceive()
behaves just like
mq_receive(),
except that if the queue is empty and the
O_NONBLOCK
flag is not enabled for the message queue description, then
abs_timeout
points to a structure which specifies how long the call will block.
This value is an absolute timeout in seconds and nanoseconds
since the Epoch, 1970-01-01 00:00:00 +0000 (UTC),
specified in the following structure:

SEE ALSO

COLOPHON

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